Adaptive seek latency

Abstract

The disclosure is related to systems and methods for adaptive seek latency in a rotating storage device. In one example, a servo control circuit can be configured to determine a seek latency and provide the seek latency to another controller or control circuit that is configured to implement the seek latency. Further, the servo control circuit can calculate the seek latency based on a measurement of a variable condition of a device and the servo controller can adjust the seek latency as the condition varies. In some examples, the variable condition may include power measurements, temperature measurements, a fault rate, other conditions, or any combination thereof. Also, different algorithms for calculating the seek latency may be implemented based on a selected goal of the system, such as power savings or reduced head vibration.

What is claimed is: 
     
       1. A device comprising:
 a servo control circuit configured to:
 determine an additional latency time for a seek command; 
 provide the additional latency time to a data controller; and 
 
 the data controller configured to add the additional latency time to a seek time representing an amount of time until a specific sector of a data storage medium is in a position to be accessible to a read mechanism, the data controller configured to determine a seek latency by adding the additional latency time and a variable padding time to the seek time, the variable padding time representing an amount of time delay from a seek arrival at a sector to when data of the sector is transferred. 
 
     
     
       2. The device of  claim 1  further comprising the servo control circuit configured to vary the additional latency time per each seek command. 
     
     
       3. The device of  claim 1  further comprising the servo control circuit configured to determine the additional delay in real-time based on one or more variable conditions, adjust the additional delay based on the one or more variable conditions, and provide the additional delay to the data controller to be added to a next pending seek command. 
     
     
       4. The device of  claim 1  wherein the additional delay and the padding time are variable for each seek command. 
     
     
       5. The device of  claim 3  further comprising:
 a memory including a command queue; 
 an interface to receive commands from a host; and 
 a data transducer to read data from a rotatable data storage medium having servo information thereon; 
 the servo control circuit configured to:
 determine a position of the data transducer with respect to the rotatable data storage medium; and 
 provide the additional latency time to the data controller to add the additional latency time to a next pending seek command in the command queue. 
 
 
     
     
       6. The device of  claim 3  wherein the one or more variable conditions comprise a temperature of the device. 
     
     
       7. The device of  claim 3  wherein the one or more variable conditions comprise a temperature of a component of the device. 
     
     
       8. The device of  claim 3  wherein the one or more variable conditions comprise a measurement of power consumption. 
     
     
       9. The device of  claim 3  wherein the one or more variable conditions comprise an off-track fault rate. 
     
     
       10. A method comprising:
 receiving a value based on a condition of a data storage device; and 
 adjusting an additional delay added to a seek time for a pending data access command of the data storage device based on the value, the seek time representing an amount of time until a specific sector of a data storage medium is in a position to store data, the seek time includes a just-in-time (JIT) seek time and a variable JIT padding time representing an amount of time delay from a seek arrival at a sector to when the data of the sector is transferred. 
 
     
     
       11. The method of  claim 10  further comprising the additional delay is received from a servo circuit for each seek command and applied to a next pending seek command. 
     
     
       12. The method of  claim 11  further comprising implementing a power saving mode where the variable JIT padding time is kept at a constant amount and an extended JIT seek time is calculated based on the additional delay. 
     
     
       13. The method of  claim 12  wherein the value comprises a temperature. 
     
     
       14. The method of  claim 11  further comprising implementing a head vibration reduction mode that includes setting a variable JIT seek time and the variable JIT padding time, where the variable JIT seek time may vary for each seek during the head vibration reduction. 
     
     
       15. The method of  claim 14  wherein the value comprises a fault rate. 
     
     
       16. The method of  claim 11  further comprising determining the additional delay in real-time and providing the additional delay to a controller in response to a seek command, wherein the controller adds the additional delay to a next pending seek command. 
     
     
       17. A device comprising:
 an interface circuit to receive commands; 
 a memory having a command queue to store pending commands; 
 a data storage controller to execute the pending commands to access a data storage medium; and 
 a servo controller configured to calculate an additional delay and to add the additional delay a variable padding time to a seek time of a next pending seek command to determine a seek latency, the variable padding time representing an amount of time delay from a seek arrival at a sector to when data of the sector is transferred. 
 
     
     
       18. The device of  claim 17  further comprising the servo controller configured to calculate the additional delay based on a measurement of a variable condition of the device and the servo controller configured to adjust the additional delay as the condition varies. 
     
     
       19. The device of  claim 17 , further comprising the seek time includes a just-in-time (JIT) seek time. 
     
     
       20. The device of  claim 17 , further comprising the variable padding time includes a variable JIT padding time representing an amount of time delay from a seek arrival at a sector to when the data of the sector is transferred.